Field of the Invention
Various embodiments of the present invention relate to an anti-surge valve, and particularly, to a commercial vehicle turbocharger system in which an anti-surge valve is realized so as not to be adversely affected by high-temperature and high-pressure charge air, which is introduced thereinto, containing blow-by oil mist by means of double separation of a chamber having an increased vertical height, and to which a separation chamber type anti-surge valve is applied so that surge noise is significantly reduced and the turbocharger system is operable while securing durability.
Description of Related Art
In general, a turbocharger applied to a commercial CNG (Compressed Natural Gas) vehicle is affected by surge noise caused when pulsation, which is generated by a throttle valve being closed when an accelerator pedal is turned off after acceleration, occurs in a supercharging portion of the turbocharger.
For this reason, an anti-surge valve is applied to the commercial CNG vehicle together with the turbocharger so as to reduce surge noise so that durability of the turbocharger is prevented from being deteriorated.
For example, the anti-surge valve reduces surge noise in such a manner that a negative pressure of an intake manifold (at a rear end of the throttle valve, approximately 1.18 bar) generated by closure of the throttle valve acts on the anti-surge valve such that an outlet thereof is opened and a turbocharger side high pressure (at a front end of the throttle valve, approximately 1.22 bar) is released to a duct through the opened outlet. To this end, the anti-surge valve includes a rubber diaphragm, a diaphragm operation portion which is integrally formed with the throttle valve and is opened and closed by a pressure differential at the front and rear of the throttle valve, and an air flow portion.
As such, the anti-surge valve reduces surge noise so that durability of the turbocharger may be secured.
However, the rubber diaphragm of the anti-surge valve may be exposed to turbocharger charge air of high-temperature and high-pressure when opened and closed by the pressure differential at the front and rear of the throttle valve. Particularly, since the rubber diaphragm comes into direct contact with blow-by oil mist contained in the turbocharger charge air of high-temperature and high-pressure, durability of the rubber diaphragm may be deteriorated.
The durability deterioration of the rubber diaphragm brings about tearing of the rubber diaphragm and the anti-surge valve is integrally formed with the diaphragm to thereby generate eccentricity during movement of the diaphragm operation portion and air flow portion connected to the diaphragm. Accordingly, this causes that the anti-surge valve is difficult to operate normally.
Furthermore, the abnormal operation of the anti-surge valve brings about an engine hesitation phenomenon in which a vehicle lurches when a pressure introduced into the rear end of the throttle valve is supplied to an engine in a deceleration section, and a power shortage phenomenon generated when a flow rate of air supplied to the engine is decreased by releasing of an intake line pressure to the front end of the turbocharger during acceleration.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.